Food allergy is a serious nutritional problem in children and adults. Basically, any food that contains protein has the potential to elicit an allergic reaction in a percentage of the human population. Most food-allergic reactions are attributable to cows' milk, eggs, fish, crustaceans, peanuts, soybeans, tree nuts and wheat. Sometimes referred to as “the Big Eight”, it is estimated that these foods or food groups account for more than 90% of all food allergies in the United States. (Taylor et al., (1999) Nutrition Today 34:15-22).
The allergens in foods are almost always naturally occurring proteins. Although foods contain millions of individual proteins, only a comparative few food proteins have been documented as being allergens. Some foods are known to contain multiple allergenic proteins, including soybeans, peanuts, cows' milk and eggs. (Burks et al., (1988) J. Allergy Clin. Immunol. 81:1135-42; Thanh et al., (1976) J. Agr. Food Chem. 24:1117-21).
Improved isolation techniques resulting in better flavor and increased functionality has resulted in widespread use of soy protein isolates and concentrates in a variety of food products in amounts that could trigger an allergic reaction in soybean-sensitive individuals. Soybean protein allergies pose a significant problem for large numbers of people because soybean protein is now a common constituent of many processed foods. For sensitive individuals, avoiding soybean products is difficult and poses significant limitations in choosing processed and convenience foods. Since the incidence of soybean-related food allergies is increasing in many countries including the U.S. (Taylor et al., Chemistry of Food Allergens in Food Allergy, Chandra R. K. (ed.): Food Allergy, Nutrition Research Education Foundation, 1987, pp 21-44), there is an ever-growing need to develop hypoallergenic soybean products to address this issue.
The major human allergen of soybean seeds is a protein designated Gly m Bd 30K also referred to as P34 because this protein has been shown to have an N-terminal amino acid sequence and amino acid composition identical to that of the soybean seed 34 kDa seed vacuolar protein, P34. Gly m Bd 30K was described by (Ogawa et al., (1991) J. Nutr. Sci. Vitaminol. 37:555-565), as a 30-kDa mol wt protein, a minor constituent of the 7S globulin fraction. Gly m Bd 30K is an outlying member of the papain-superfamily of cysteine-proteases and is present in processed food products that contain soybean protein. (Yaklich et al., (1999) Crop Science 39:1444). Results have indicated that it may not be possible to eliminate P34 from the food supply by breeding with an improved germplasm base. (Yaklich et al., (1999) Crop Science 39:1444). Thus, the elimination of P34 from soybean seeds, as well as other allergens allergens such as Gly m IA, Gly m IB, rGLY m3 and Glycinin G1 (AlaB1b), by using recombinant technology not only would enhance food safety but it would make the use of soybean products available to sensitive individuals.